Ophthalmological surgery technique with active patient data card

ABSTRACT

An ophthalmological laser surgery system having a laser, associated elements for delivering an optical beam from the laser to a patient eye location, a control unit for controlling the operation of the system and a system input/output device, is enabled by a patient data card. The data card originally contains both patient background and system control information, which is transferred to the control unit via the input/output device. During system operation, newly generated information, such as laser beam power, is stored in the data card to provide an independent record of the surgical procedure actually performed. After one use, the data card is invalidated to prevent further use.

This is a divisional application of U.S. patent application Ser. No.08/904,199, filed Jul. 31, 1997 (now U.S. Pat. No. 6,364,873; which is acontinuation application of U.S. patent application Ser. No. 07/666,840,filed Mar. 8, 1991 (now U.S. Pat. No. 6,296,634; the full disclosures ofwhich are herein incorporated by reference; this application is alsorelated to U.S. patent application Ser. No. 09/137,975, filed Aug. 21,1998 (now U.S. Pat. No. 6,106,513.

BACKGROUND OF THE INVENTION

This invention relates to ophthalmological surgery techniques whichemploy an ultraviolet laser used to provide ablative photodecompositionof the surface of the cornea in order to correct vision defects.

Ultraviolet laser based systems and methods are known for enablingophthalmological surgery on the external surface of the cornea in orderto correct vision defects by the technique known as ablativephotodecomposition of the cornea. In such systems and methods, theirradiated flux density and exposure time of the cornea to theultraviolet laser radiation are so controlled as to provide a surfacesculpting of the cornea to achieve a desired ultimate surface change inthe cornea, all in order to correct an optical defect. Such systems andmethods are disclosed in the following U.S. patents and patentapplications, the disclosures of which are hereby incorporated byreference: U.S. Pat. No. 4,665,913 issued May 19, 1987 for “Method forOphthalmological Surgery”; U.S. Pat. No. 4,669,466 issued Jun. 2, 1987for “Method and Apparatus for Analysis and Correction of AbnormalRefractive Errors of the Eye”; U.S. Pat. No. 4,732,148, issued Mar. 22,1988 for “Method for Performing Ophthalmic Laser Surgery”; U.S. Pat. No.4,770,172 issued Sep. 13, 1988 for “Method of Laser-Sculpture of theOptically Used Portion of the Cornea”; U.S. Pat. No. 4,773,414 issuedSep. 27, 1988 for “Method of Laser-Sculpture of the Optically UsedPortion of the Cornea; U.S. patent application Ser. No. 109,812 filedOct. 16, 1987 for “Laser Surgery Method and Apparatus”; and U.S. patentapplication Ser. No. 081,986 filed Aug. 5, 1987 for “PhotorefractiveKeratectomy”.

The art has now advanced to the stage at which self-contained laserbased systems are sold as stand alone units to be installed in asurgeon's operatory or a hospital, as desired. Thus, hospitalization isnot necessarily required in order to perform such ophthalmologicalsurgery. Such systems typically include a p.c. (personal computer) typework station, having the usual elements (i.e., keyboard, video displayterminal and microprocessor based computer with floppy and hard diskdrives and internal memory), and a dedicated microprocessor basedcomputer which interfaces with the p.c. work station and appropriateoptical power sensors, motor drivers and control elements of theultraviolet laser, whose output is delivered through an optical systemto the eye of the patient. In use, after the patient has beenaccommodated on a surgery table or chair, the system is controlled bythe operator (either the surgeon or the surgeon and an assistant) inorder to prepare the system for the delivery of the radiation to thepatient's eye at the appropriate power level and spatial location on thecorneal surface. Patient data is typically entered, either manually viathe p.c. work station keyboard or from a memory storage element (e.g., afloppy disk), and the system automatically calculates the beam deliveryparameters and displays the resulting calculations on the video displayterminal, with an optional hard-copy printout via a suitable printer.The laser is also prepared to deliver the appropriate radiation inaccordance with the calculated beam delivery parameters, and thedelivery system optics are likewise preconditioned. In some systems, aprovision is made for permanently recording on a plastic card made ofPMMA (polymethylmethacrylate) a spot image of the laser beam used in thesurgical operation. This spot is recorded prior to the operation toensure that the beam power is properly adjusted and to provide apermanent record of the beam used. PMMA is typically used due to thecharacteristic of this material of having a closely similar ablativephotodecomposition response to that of the human corneal tissue. Afterthe surgery has been performed, the resultant data is typically madepart of a permanent record, which becomes part of the patient's file.

Such systems and methods are presently emerging as the technique ofchoice for ophthalmological surgery to correct various vision defects inhumans. However, as a relatively recent development this technique ingeneral is still subject to close scrutiny and careful evaluation by themedical community as well as by certain regulatory agencies (e.g., theFood and Drug Administration in the United States of America). Althoughthe p.c. work station provides some ability to collect pertinentinformation for the evaluation of system performance and to aid intracking the efficacy of the surgical technique, as well as to providequality control assistance to the manufacturer of the system, existinglaser systems lack a simple effective control mechanism for thispurpose.

SUMMARY OF THE INVENTION

The invention provides a simple control mechanism for monitoring theactual usage of ophthalmological laser surgery systems, which isrelatively inexpensive to implement and highly reliable in trackinginformation relating to machine usage and patients' data relating tosurgeries performed.

In a first aspect of the invention, an ophthalmological laser surgerysystem is provided with a patient data card read/write device forcontrolling and monitoring the operation of the laser surgical system inconjunction with a precoded patient data card. The data card andread/write device interact in such a manner that the laser surgicalsystem cannot be operated unless an authorized patient data card isinserted into the read/write device. Once the patient data card isrecognized by the system as a legitimate and authorized card, the systemis unlocked for normal operation. Preferably, during normal operationthe beam delivery parameters calculated by the system, as well as otheractual surgical operation data (such as the configuration of thedelivery system optics, the duration and power of the laser irradiationof the patient's cornea, the coordinates of the projected laser beam,and the like) are recorded on the patient data card to form a permanentrecord independently of or parallel to the information stored in thep.c. work station. Also, a test spot of the actual laser beam can bepermanently recorded onto the patent data card by directing the beamonto a preselected region of the data card to perform an ablation ofthat region.

In another aspect, the invention comprises a patient data card havingencoded therein several kinds of information for use in evaluating andcontrolling a laser based ophthalmological surgery system and surgeriesperformed therewith. A first type of information comprises anauthorization code required by the surgery system for enablement to anoperative state. Preferably, this first type of information includes acode unique to a specific laser surgery system so that a given patientdata card can be used on one and only one machine. Further informationstored on the card identifies all authorized surgeons, the patient, thepatient's past history, the desired prescription or other identifyinginformation regarding the permissible surgery to be performed on thatpatient, and preoperative diagnostic information for checking the lasersystem settings. The card may also contain downloadable software forcontrolling or altering the operation of the laser system. The card mayalso contain a photograph of the patient, one or more fingerprints ofthe patient, or a combination of this or other identifier information.In addition, the card preferably contains an ablation region capable offorming and retaining a physical laser ablation imprint of the intendedlaser treatment for future analysis and comparison.

In use, the card is pre-coded by the system manufacturer or some othercontrol agency, and issued for use with a specific system. If desired,the patient information may be intentionally left blank and provided bythe surgeon or some other authorized person prior to the surgicaloperation. After the surgery has been performed, the actual datapertaining to the surgery is encoded onto the card for future use.Preferably, the data card is issued for a single surgery and isinvalidated immediately thereafter, e.g., by permanently recording aninvalidation character onto the card.

The data stored on the card can be transferred from the card to any oneof a number of interested parties. The surgeon, for example, maytransfer the information from the card to a patient data file or someother master file maintained by the surgeon. This can be done at thedata card read/write device and the p.c. work station at the site of thelaser system. In addition, the information recorded in the patient datacard can be transferred to the system manufacturer's files either fromthe surgeon's office using the p.c. work station and a modem, ordirectly from the patient data card. In the latter case, the card can bephysically transferred to the manufacturer's office by either thesurgeon or the patient, or the patient may visit one of a number ofconvenient sites having a compatible card reader device.

For a fuller understanding of the nature and advantages of theinvention, reference should be had to the ensuing detailed descriptiontaken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an ophthalmological laser surgery systemincorporating the invention; and

FIG. 2 is a plan view of a patient data card according to the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the drawings, FIG. 1 illustrates a block diagram of anophthalmological surgery system incorporating the invention. As seen inthis Fig., a p.c. work station 10 is coupled to the single boardcomputer 21 of a laser surgery unit 20 by means of a first busconnection 11. P.C. work station 10 and the subcomponents of lasersurgery unit 20 are known components and preferably comprise theelements of the VISX TWENTY/TWENTY excimer laser system available fromVisx, Incorporated of Sunnyvale, Calif. Thus, the laser surgery system20 includes a plurality of sensors generally designated with referencenumeral 22 which produce feedback signals from the moveable mechanicaland optical components in the laser optical system, such as the elementsdriven by an iris motor 23, an image rotator 24, an astigmatism motor 25and an astigmatism angle motor 26. The feedback signals from sensors 22are provided via appropriate signal conductors to the single boardcomputer 21, which is preferably an STD bus compatible single boardcomputer using a type 8031 microprocessor. The single board computer 21controls the operation of the motor drivers generally designated withreference numeral 27 for operating the elements 23-26. In addition,single board computer 21 controls the operation of the excimer laser 28,which is preferably an argon-fluorine laser with a 193 nanometerwavelength output designed to provide feedback stabilized fluence of 160mJoules per cm² at the cornea of the patient's eye 30 via the deliverysystem optics generally designated with reference numeral 29. Otherancillary components of the laser surgery system 20 which are notnecessary to an understanding of the invention, such as a highresolution microscope, a video monitor for the microscope, a patient eyeretention system, an ablation effluent evacuator/filter, and the gasdelivery system, have been omitted to avoid prolixity. Similarly, thekeyboard, display, and conventional p.c. subsystem components (e.g.,flexible and hard disk drives, memory boards and the like) have beenomitted from the depiction of the p.c. work station 10.

P.C. work station 10 is actively intercoupled with a patient data cardwriter/reader 40 designed to interact with an individual patient datacard 42 schematically illustrated in FIG. 2. As seen in FIG. 2, thepatient data card 42 is similar to a credit card and has a first surfaceregion 43 for carrying visually readable information, such as the nameof the patient, the card supplier (e.g., laser surgery systemmanufacturer, health care provider or the like), the patient's name andany other information which is deemed desirable for visual presentation.Another region 44 is reserved for information identifying the authorizedbearer or user of the card, such as a fingerprint or a photograph of thepatient. An ablation region or target area 45 is provided forpermanently recording the laser beam operating characteristics justprior to or after performance of a surgery. For this purpose, ablationregion 45 may comprise an insert of a polymethylmethacrylate, which asnoted above has close matching ablative photodecompositioncharacteristics to that of human corneal tissue. Alternatively, theentire card 42 may be fabricated of PMMA, or some other substance suchas polycarbonate which has similar ablation characteristics to PMMA. Thepurpose of the ablation region 45 is to provide a permanent ablativephotodecomposition record produced by the actual laser beam used in thesurgery.

Patient data card 42 is preferably an optical memory card of the typemanufactured and marketed by Drexler Technology Corporation under thetrademark LaserCard, which is a credit card sized optical data storagedevice capable of holding more than four megabytes of write once/readmany (WORM) data. Similarly, the data card writer/reader 40 may be aknown unit compatible with the Drexler optical memory card. If desired,a suitable magnetic memory card may be employed along with a compatiblecard writer/reader device 40.

The patient data card 42 is initially provided with read onlyinformation optically encoded into the subsurface recording layers (notvisible in FIG. 2). This information includes the serial number or otheridentifying characteristic of a specific laser surgery system 20 so thatthe data card 42 can only be used with a specific system 20. The purposefor this limitation is to provide controlled information relating to theamount of use of the system 20 and a match between the identity of thesystem 20 and the actual beam used during the eye surgery (the ablationrecord permanently formed in ablation region 45 of the data card 42). Inaddition, other qualifying data may be permanently recorded by the cardproducer, such as the personal identification number of the surgeon orsurgeons (or other personnel) qualified to operate the specific system20, the prescription of the patient to control the amount and type oflaser surgery on a particular patient, the eye upon which surgery willbe allowed (e.g., right eye only, left eye only or both, including anydifferences in prescription between the two eyes), and any otherrelevant and pertinent information deemed desirable for monitoring thespecific patient and the specific system 20.

In order to render the system 20 operative, an authorized data card 42must be read by the writer/reader 40, and this information must then bepresented to the p.c. work station 10, which functions as the mastercontrol for the system 20. Once an authorized card has been inserted andidentified, the operation of the system 20 proceeds in a somewhatconventional fashion in that the beam delivery parameters are calculatedin the p.c. work station 10 and transferred to the single board computer21 for control of the various motors 23-26, the laser 28 and thedelivery system optics 29. At some time during the surgery procedure,preferably just prior to the actual irradiation of the eye 30, the datacard 42 may be installed in a fixture (not shown) in the output beampath of the laser 28 (i.e., within the delivery system optics 29 or atthe output side thereof) and the laser 28 is pulsed at the surgical rateand power to form the permanent record of the laser beam in the ablationregion 45. Thereafter, the surgery is performed and the post operationdata is measured, calculated and stored in an appropriate memorylocation within the p.c. work station 10. Certain information may thenbe recorded onto the patient data card 42 by means of the data cardwriter/reader 40 so that the data card 42 obtains post operativeinformation useful for monitoring purposes. For example, the date of theoperation, the total length of the exposure of the corneal surface ofthe eye 30 to the laser beam 28, the pulse duration, the time betweenpulses, the exact coordinate settings of the laser beam radiationthroughout the operation may all be recorded on the patient data card42. This information is then available until destruction of the card forany informational purposes the surgeon, the patient, the healthinsurance company, the regulatory agency and the system manufacturer mayrequire. In addition, if desired the card 42 may be permanently alteredto prevent repeated use with specific surgery system 20 or any othersystem 20 as an added check on the operational use of a specific system20.

The patient data card 42 may contain program instructions required forthe operation of the system 20. In such an embodiment, p.c. workstation10 receives the necessary program instructions from the card 42 using aconventional software downloading operation at the beginning of systemoperation. At the conclusion of system operation, the programinstructions resident in the p.c. workstation 10 are erased to preventsubsequent operation of system 20 without a fresh data card 42.

As will now be apparent, laser surgery systems provided with thepersonal data card functioning as a control token offer an unparalleleddegree of control over the use of the surgery system and afford arigorous information gathering capability for quality control andmonitoring studies. In particular, every single use of a given surgerysystem 20 can be accurately monitored by use of the patient data card42, and the actual operating characteristics and optical parameters canbe permanently stored in an independently verifiable manner for futurestudy. Such a capability is particularly important for laser surgerysystems still subject to regulatory control, as well as to fullyapproved laser surgery systems for which cumulative historical data ishighly desirable. The added cost of the data card reader/writer 40 isnominal compared to the overall system, and the patient data card is nomore inconvenient to carry and use than any conventional credit card.

While the above provides a full and complete disclosure of the preferredembodiments of the invention, various modifications, alternateconstructions and equivalents may be employed as desired. For example,while the invention has been described with specific reference to anoptically encoded data card 42, data cards having read/write storagecapability and using magnetic or semiconductor technology may beemployed, as desired. In addition, other laser surgery systems than theVISX system noted above can be used to implement the invention.Therefore, the above description and illustrations should not beconstrued as limiting the invention, which is defined by the appendedclaims.

1. A method of preventing unauthorized use of a system for ablating thecornea by selective irradiation, said method comprising the steps of:(a) recording predetermined information including information indicatingwhich of the eyes of a patient upon which surgery will be allowed on adata carrier that is independent from said system; (b) reading saidinformation indicating which of the eyes of a patient upon which surgerywill be allowed from said data carrier into said system; and (c)enabling said system to perform corneal ablation upon the eyes of thepatient indicated in said predetermined information.
 2. The method ofclaim 1, wherein the data carrier containing the predeterminedinformation is in the form of a system manufacturer file.
 3. The methodof claim 2, wherein the reading step (b) further includes transferringthe predetermined information from the system manufacturer file to thesystem.
 4. The method of claim 3, wherein the predetermined informationon the system manufacturer file is transferred to the system using amodem.
 5. A method of preventing unauthorized use of a system forablating the cornea by selective irradiation, the method comprising thesteps of: (a) recording predetermined enabling information on a datacarrier that is independent from the system; (b) presenting thepredetermined enabling information to the system; and (c) preventing theuse of the system unless the predetermined enabling information on thedata carrier is accepted by the system.
 6. The method of claim 5,wherein the predetermined enabling information is presented to thesystem using a modem.
 7. The method of claim 6, wherein thepredetermined enabling information comprises an authorization code. 8.The method of claim 6, wherein the predetermined enabling informationcomprises a code unique to a specific laser surgery system so that thepredetermined enabling information can only be used on one and only onesystem.
 9. The method of claim 6, wherein the predetermined enablinginformation comprises the identities of surgeons authorized to operatethe system.
 10. The method of claim 6, wherein the predeterminedenabling information comprises the identity of a patient.
 11. The methodof claim 6, wherein the predetermined enabling information comprises apast history of a patient.
 12. The method of claim 6, wherein thepredetermined enabling information comprises the desired prescription tobe performed on a patient.
 13. The method of claim 6, wherein thepredetermined enabling information comprises preoperative diagnosticinformation for checking the laser system settings.
 14. The method ofclaim 6, wherein the data carrier further comprises downloadablesoftware for controlling or altering the operation of the laser system.15. The method of claim 6, wherein the data carrier further includes aphotographic image of the patient.
 16. The method of claim 6, whereinthe data carrier further includes fingerprint data of a patient.
 17. Amethod of preventing unauthorized use of a laser surgery systemcomprising the steps of: (a) providing a system control unit forcontrolling the operation of said laser surgery system; (b) providing aunique identifier specifying a first identity of a surgeon to saidsystem control unit; (c) providing an independent data carriercontaining predetermined information including (1) an authorizedidentity of a surgeon authorized to operate said system and (2) anindication of which of the eyes of a patient upon which said lasersurgery system should operate; (d) comparing said first identity withsaid authorized identity; and (e) enabling the system to permit acorneal ablation procedure if the step (d) of comparing indicates amatch in identities.
 18. A method for preventing unauthorized use of alaser surgery system used to ablate the cornea by selective irradiation,said method comprising the steps of: (a) providing a system control unitfor controlling the operation of said laser surgery system; (b)providing a unique identifier to said system control unit, said uniqueidentifier specifying a first identity of a surgeon; (c) providing anindependent data carrier containing predetermined information including(1) an authorized identity of a surgeon authorized to operate saidsystem and (2) an indication of which of the eyes of a patient should beoperated upon; (d) comparing said first identity to said authorizedidentity; and (e) enabling said system to perform a corneal ablationprocedure on the eyes of the patient indicated in said predeterminedinformation if the step (d) of comparing indicates a match inidentities.
 19. The method of claim 18, wherein the data carriercontaining the predetermined information is in the form of a systemmanufacturer file.
 20. The method of claim 19, wherein the predeterminedinformation is transferred from the system manufacturer file to thesystem prior to the comparing step (d).
 21. The method of claim 20,wherein the predetermined information on the data carrier is transferredto the system using a modem.
 22. A regulatory control method for usewith a laser eye surgery system, the method comprising: issuing enablinginformation including a first authorization code from a manufacturer orother control agency; entering patient data for a particular patientinto a system control unit of the laser eye surgery system; reading theenabling information into the system control unit, wherein the systemcontrol unit renders the laser eye surgery system operative in responseto the enabling information; performing a corneal ablation procedure onthe patient with the operative system; and preventing operation of thelaser eye surgery system after the ablation procedure enabled by theenabling information including the first authorization code untilenabling information including a second authorization code is issuedfrom the manufacturer or other control agency and is read into thesystem control unit.
 23. The regulatory control method of claim 22,further comprising ablating a test portion of a data card so as toproduce a permanent photo decomposition record of a laser beam used inthe corneal ablation procedure.
 24. The regulatory control method ofclaim 23, wherein the first and second authorization codes are adaptedfor use with only a specific laser ablation system so that the ablatedtest portion of the data test card can be matched to the laser beam. 25.The regulatory control method of claim 22, wherein the enabling dataissued by the manufacturer or other control agency includes at least oneof an identification of a person qualified to operate the laser eyesurgery system, the prescription of the patient, and an identificationof which eye of the patient can be treated.
 26. The regulatory controlmethod of claim 22, wherein the enabling data issued by the manufactureror other control agency allows the manufacturer to control at least oneof an amount and a type of laser surgery which can be performed by anoperator of the laser eye surgery system.
 27. A method according toclaim 1 and further comprising the step of providing said data carrierin the form of a data card.
 28. A regulatory control method for use witha laser eye surgery system, the method comprising: issuing enablinginformation including an authorization code; entering patient data for aparticular patient into a system control unit of the laser eye surgerysystem; reading the enabling information issued by the manufacturer orother control agency into the system control unit, wherein the systemcontrol unit renders the laser eye surgery system operative in responseto the enabling information; performing a corneal ablation procedure onthe patient with the operative system; and transferring the patient datato the manufacturer.
 29. The regulatory control method of claim 28,wherein the transferring step is performed from the system control unitusing a modem.
 30. A regulatory control method for use with a laser eyesurgery system, the method comprising: issuing enabling informationincluding a first authorization code from a manufacturer or othercontrol agency; entering patient data for a particular patient into asystem control unit, wherein the system control unit is at leastpartially controllable by the manufacturer or other control agency, andis coupled with the laser eye surgery system; reading the enablinginformation into the system control unit, wherein the system controlunit renders the laser eye surgery system operative in response to theenabling information; performing a corneal ablation procedure on thepatient with the operative system; and preventing operation of the lasereye surgery system after the ablation procedure enabled by the enablinginformation including the first authorization code until enablinginformation including a second authorization code is issued from themanufacturer or other control agency and is read into the system controlunit.
 31. The regulatory method of claim 30, further comprising locatingthe system control unit at the manufacturer or other control agency. 32.The regulatory method of claim 30, further comprising using a modem tocouple the system control unit with the laser surgery system.
 33. Theregulatory method of claim 30, further comprising transmittinginformation related to the usage of the laser surgery system from thelaser surgery system to the system control unit using the modem.
 34. Theregulatory method of claim 30, further comprising entering the patientdata into the system control unit using a modem.